High-fidelity modelling of composite specimens manufactured with the automated fibre placement technique

Abstract

Thermoplastic Automated Fiber Placement (AFP) enables the near net shape production of individual lightweight structures, without post-consolidation by means of in-situ consolidation. The placement of multiple tapes with a robotic setup increases the layup accuracy and reduces the amount of manufacturing defects. In spite of this, gaps between the placed tapes or overlaps of these tapes can still cannot be completely avoided, particularly for more complex double-curved structures. Without a post-consolidation process, the defects cannot be mitigated in a subsequent autoclave- or hot-press process. While the precise localization and quantification of these defects is possible with ultrasonic scans, their influence on the local mechanical performances of the laminate cannot be foreseen. To this end, a high-fidelity modelling of AFP-manufactured parts is addressed in this work. The present approach takes benefit of planned or measured paths of every single tape to recreate the geometrical influence of defects and generate a simulation model of the as-built structure. The manufacturing data (tape thickness, tape angle etc.), is mapped on a finite-element model made of layered thick-thick shell elements using a closest point algorithm. Failure mechanisms in the consolidated tapes is simulated with the material card *MAT_262. Additionally, delamination mechanisms are reproduced using the cohesive zone model *MAT_240. The high-fidelity modelling approach is used to virtually investigate the effect of particular defects on the compression and delamination strength of composite samples. The present contribution details the suggested methodology and illustrates its potential to understand manufacturing effects in AFP production. First experimental and numerical investigations are presented.